Eye movements of normal and hyperactive children are recorded with electrooculography (EOG) and compared for differences in ocular pursuit. The stimulus is a 1 degree dot of light moving sinusoidally or at constant velocity over 30 degrees of the central visual field. Attention is controlled by recording the reaction to dimming of the spot of light. The size and number of saccades superimposed on pursuit, the retinal error, and the frequency response of the pursuit system will be determined. We have shown that hyperactives make more and larger saccadic eye movements than normals during pursuit. This difference is present with or without the attentional task and disappears on medication. This suggests that characteristics of the pursuit system of hyperactives and normals are different. We now propose to complete the analysis of pursuit by measuring retinal error at various velocities and studying the frequency response of the pursuit system using spectral analysis. This should help determine which are the best parameters to differentiate between hyperactives and normals. Control groups will be studied to determine the specificity of the findings in hyperactivity. The goal of the research is to gain insight into the pathophysiology of the hyperkinetic syndrome and to develop measures which will aid in the diagnosis of hyperkinesis and the evaluation of treatment.